Example 1: Golang pass nil as an argument In the below example, if the parameter iszero value, set it with the default value: go packagemainimport"fmt"funcmain(){ fmt.Println(GetStudentInfo("","")) fmt.Println(GetStudentInfo("Anna","")) fmt.Println(GetStudentInfo("","+145366"))...
}fori, _ := range *pass { pass[i]= strconv.Itoa(100+i) } fmt.Printf("int point array [%p] init value: %v\n", &paii, *paii) fmt.Printf("string point array [%p] init value: %v\n", &pass, *pass) fmt.Println("---") paii[0] =1pass[0] ="1"fmt.Printf("%v\n==...
BenchmarkConvertReflect-410000000002.247ns/op0B/op0allocs/opPASS -benchtime=2s', 依次递增 b.N 直至运行时间超过 2s-count=3,执行 3 轮-benchmem,b.ReportAllocs,展示堆分配信息,0 B/op, 0 allos/op 分别代表每次分配了多少空间,每个 op 有多少次空间分配-cpu='2,4',依次在 2 核、4 核下进行...
go 中 reflect 机制涉及到 2 个类型,reflect.Type 和 reflect.Value,reflect.Type 是一个 Interface,其不在本章介绍范围内。 reflect.Value 定义位于value.go、type.go,其定义与 eface 类似: type Value struct { typ *rtype // type._type ptr unsafe.Pointer flag } // rtype must be kept in sync ...
argument is a type, not a value. Unlike new, make's return type is the same as the type ...
Golang is apass by valuelanguage, so any time we pass a value to a function either as a receiver or as an argument that data is copied in memory and so the function by default is always going to be working on a copy of our data structure. We can address this problem and modify the...
{})// Group allows to start a group of goroutines and wait for their completion.typeGroupstruct{wg sync.WaitGroup}func(g*Group)Wait(){g.wg.Wait()}// StartWithChannel starts f in a new goroutine in the group.// stopCh is passed to f as an argument. f should stop when stopCh ...
cannot use b (type ByteSlice) as type io.Writer in argument to fmt.Fprintf: ByteSlice does not implement io.Writer (Write method has pointer receiver) Go语言规范有这样的规定: The method set of any other named type T consists of all methods with receiver type T. The method set of the ...
= kindFunc {throw("runtime.SetFinalizer: second argument is "+ ftyp.string()+", not a function")} ft :=(*functype)(unsafe.Pointer(ftyp))if ft.dotdotdot(){throw("runtime.SetFinalizer: cannot pass "+ etyp.string()+" to finalizer "+ ftyp.string()+" because dotdotdot")}if ft...
Here's a fairly succinct example. We're trying to pass a function as an argument, but the argument types differ becausefmt.Stringerandmain.Stringerare different interfaces, even though they are compatible: package main import ( "fmt" "time" ) type Stringer interface { String() string } func...